The evolution of the brain, the human nature of cortical circuits and intellectual creativity

The tremendous expansion and the differentiation of the neocortex constitute two major events in the evolution of the mammalian brain. The increase in size and complexity of our brains opened the way to a spectacular development of cognitive and mental skills. This expansion during evolution facilitated the addition of microcircuits with a similar basic structure, which increased the complexity of the human brain and contributed to its uniqueness. However, fundamental differences even exist between distinct mammalian species. Here, we shall discuss the issue of our humanity from a neurobiological and historical perspective

l-Amino Acid Production by a Immobilized Double-Racemase Hydantoinase Process: Improvement and Comparison with a Free Protein System

Protein immobilization is proving to be an environmentally friendly strategy for manufacturing biochemicals at high yields and low production costs. This work describes the optimization of the so-called “double-racemase hydantoinase process,” a system of four enzymes used to produce optically pure l-amino acids from a racemic mixture of hydantoins. The four proteins were immobilized separately, and, based on their specific activity, the optimal whole relation was determined. The first enzyme, d,l-hydantoinase, preferably hydrolyzes d-hydantoins from d,l-hydantoins to N-carbamoyl-d-amino acids. The remaining l-hydantoins are racemized by the second enzyme, hydantoin racemase, and continue supplying substrate d-hydantoins to the first enzyme. N-carbamoyl-d-amino acid is racemized in turn to N-carbamoyl-l-amino acid by the third enzyme, carbamoyl racemase. Finally, the N-carbamoyl-l-amino acid is transformed to l-amino acid by the fourth enzyme, l-carbamoylase. Therefore, the product of one enzyme is the substrate of another. Perfect coordination of the four activities is necessary to avoid the accumulation of reaction intermediates and to achieve an adequate rate for commercial purposes. The system has shown a broad pH optimum of 7–9, with a maximum activity at 8 and an optimal temperature of 60 °C. Comparison of the immobilized system with the free protein system showed that the reaction velocity increased for the production of norvaline, norleucine, ABA, and homophenylalanine, while it decreased for l-valine and remained unchanged for l-methionine

Cambio estructural y exportaciones hortícolas de México hacia los Estados Unidos: análisis del comportamiento histórico de los principales productos exportados por Sinaloa

El artículo somete a prueba la hipótesis del cambio estructural en términos estadísticos a las series de tiempo de las exportaciones de México a los Estados Unidos, de cinco productos hortícolas (calabaza, berenjena, chile, pepino y jitomate) en los que Sinaloa es líder nacional. Los cinco productos representan alrededor de 46% del valor de las exportaciones hortofrutícolas mexicanas y 94.6% de las realizadas por Sinaloa. Se toman como base dos tipos de series, una en volumen y otra en valor y se analizan los periodos de 1961 a 2005 en el caso de chiles, jitomates y berenjenas; de 1965 a 2005 para pepinos y desde 1966 para calabazas, tomando como fuente los datos de la FAO. Interesa saber si la puesta en marcha del TLCAN en enero de 1994 indujo algún cambio notorio de tendencia que pudiera interpretarse como lo que en estadística se considera cambio estructural. Para ello se aplica la metodología propuesta por Vogelsang y aplicada a economía por Ben-David y Pappel. Los resultados indican que sólo las exportaciones de calabazas en términos de valor y las de berenjenas, tanto en valor como en volumen, podrían sugerir alguna relación con el TLCAN, ya que los años de cambio fueron 1996 y 1997 respectivamente. Sin embargo, se observa que si el TLCAN tuvo alguna influencia, ésta tardó de dos a tres años en aparecer, lo cual debilita la hipótesis de que dicho tratado sirvió para promover las exportaciones hortícolas seleccionadas

Production and marketing characteristics of pig production in the south of the State of Mexico

The paper examines the structure and the operation of pig production in the south of the state of Mexico, it explores the various stages that make up the commercialization process of the activity and the different actors involved, it means, all the process that is followed since the departure of the animal from the farm until its arrival as a final product for the consumer. It is also calculated the marketing margins resulting during the different stages of the process, which are used as indicators of profitability. The study was held in 2007 when a total of 17 producers of pork, two collectors, 28 retailers and 37 consumers of pig meat were polled. The objective of the survey was to gather information about the production process, actors, marketing costs and prices, and then determine the margins of marketing and characterization of pig production in the South of the state of Mexico. The results showed that at current prices, the producers participation in the final price, paid by the consumer, was 26,22 %, while the intermediaries participation was 73,78 %. The total marketing margin averaged 23,93 $/kg, from which retailers gained 23,52$/kg (98,28 %), while the remaining 0,40 $/kg was for the collectors. The traditional marketing process used in the region is: producer, collector, retailer and final consumer

Damage-driven strain localisation in networks of fibres: A computational homogenisation approach

In many applications, such as textiles, fibreglass, paper and several kinds of biological fibrous tissues, the main load-bearing constituents at the micro-scale are arranged as a fibre network. In these materials, rupture is usually driven by micro-mechanical failure mechanisms, and strain localisation due to progressive damage evolution in the fibres is the main cause of macro-scale instability. We propose a strain-driven computational homogenisation formulationbased on Representative Volume Element (RVE), within a framework in which micro-scale fibre damage can lead to macro-scale localisation phenomena. The mechanical stiffness considered here for the fibrous structure system is due to: i) an intra-fibre mechanism in which each fibre is axially stretched, and as a result, it can suffer damage; ii) an inter-fibre mechanism in which the stiffness results from the variation of the relative angle between pairs of fibres. The homogenised tangent tensor, which comes from the contribution of these two mechanisms, is required to detect the so-called bifurcation point at the macro-scale, through the spectral analysis of the acoustic tensor. This analysis can precisely determine the instant at which the macro-scale problem becomes ill-posed. At such a point, the spectral analysis provides information about the macro-scale failure pattern (unit normal and crack-opening vectors). Special attention is devoted to present the theoretical fundamentals rigorously in the light of variational formulations for multi-scale models. Also, the impact of a recent derived more general boundary condition for fibre networks is assessed in the context of materials undergoing softening. Numerical examples showing the suitability of the present methodology are also shown and discussed

Effect of collection-maturation interval time and pregnancy status of donor mares on oocyte developmental competence in horse cloning

The current limitations for obtaining ovaries from slaughterhouses and the low efficiency of in vivo follicular aspiration necessitate a complete understanding of the variables that affect oocyte developmental competence in the equine. For this reason, we assessed the effect on equine oocyte meiotic competence and the subsequent in vitro cloned embryo development of 1) the time interval between ovary collection and the onset of oocyte in vitro maturation (collection-maturation interval time) and 2) the pregnancy status of the donor mares. To define the collection-maturation interval time, collected oocytes were classified according to the slaughtering time and the pregnancy status of the mare. Maturation rate was recorded and some matured oocytes of each group were used to reconstruct zona free cloned embryos. Nuclear maturation rates were lower when the collection-maturation interval time exceeded 10 h as compared to 4 h (32/83 vs. 76/136, respectively; P = 0.0128) and when the donor mare was pregnant as compared to nonpregnant (53/146 vs. 177/329, respectively; P = 0.0004). Low rates of cleaved embryos were observed when the collection-maturation interval time exceeded 10 h as compared to 6 to 10 h (11/27 vs. 33/44, respectively; P = 0.0056), but the pregnancy status of donor mares did not affect cloned equine blastocyst development (3/49 vs. 1/27 for blastocyst rates of nonpregnant and pregnant groups, respectively; P = 1.00). These results indicate that, to apply assisted reproductive technologies in horses, oocytes should be harvested within approximately 10 h after ovary collection. Also, even though ovaries from pregnant mares are a potential source of oocytes, they should be processed at the end of the collection routine due to the lower collection and maturation rate in this group.Fil: Gambini, Andres. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; ArgentinaFil: Jarazo, Javier. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; ArgentinaFil: Karlanian, Florencia. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; ArgentinaFil: de Stéfano, Adrian. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; ArgentinaFil: Salamone, Daniel Felipe. Universidad de Buenos Aires. Facultad de Agronomía. Pabellón de Zootecnica. Laboratorio de Biotecnología Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentin

Factors influencing Safety on Construction Projects (fSCPs): types and categories

Due to the fact of activity, environment and work dynamics, the construction industry is characterised by high accident rates. Different initiatives have emerged to reduce these figures, which focus on using new methodologies and technologies for safety management. Therefore, it is essential to know the key factors and their influence on safety in construction projects (fSCPs) to focus efforts on these elements. Through a systematic literature review, based on PRISMA methodology, this article identifies, describes and categorises 100 factors that affect construction safety. It thus contributes by providing a comprehensive general framework, unifying previous studies focused on specific geographic areas or case studies with factors not considered or insufficiently disaggregated, along with an absence of classifications focused on understanding where and how factors affect the different dimensions of construction projects. The 100 factors identified are described and categorised according to the dimensions and aspects of the project in which these have an impact, along with identifying whether they are shaping or immediate factors or originating influences for the generation of accidents. These factors, their description and classification are a key contribution to improving the systematic creation of safety and generating training and awareness materials to fully develop a safety culture in organisations.This research was funded by Proyecto VRIEA-PUCV (grant number 039.429/2021). This work was supported by the CONICYT to F.M., who was the beneficiary of a pre-doctoral grant (CONICYT—PCHA/International Doctorate/2019-72200306) and by the Ministry of Science, Innovation and Universities of Spain (MICIU) through the BIMIoTICa project (RTC-2017-6454-7). The authors also acknowledge the financial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa Programme for Centres of Excellence in R&D (CEX2018-000797-S)”. Institution: Vicerrectoría de Investigación y Estudios avanzados - Pontificia Universidad Católica de Valparaíso (VRIEA-PUCV) Code Project: 039.429/2021.Peer ReviewedPostprint (published version

Factor analysis of Internet traffic destinations from similar source networks

This article is (©) Emerald Group Publishing and permission has been granted for this version to appear here (http://www.emeraldinsight.com/doi/full/10.1108/10662241211199951). Emerald does not grant permission for this article to be further copied/distributed or hosted elsewhere without the express permission from Emerald Group Publishing Limited.Purpose – This study aims to assess whether similar user populations in the Internet produce similar geographical traffic destination patterns on a per-country basis. Design/methodology/approach – We have collected a country-wide NetFlow trace, which encompasses the whole Spanish academic network, which comprises more than 350 institutions and one million users, during four months. Such trace comprises several similar campus networks in terms of population size and structure. To compare their behaviors, we propose a mixture model, which is primarily based on the Zipf-Mandelbrot power law to capture the heavy-tailed nature of the per-country traffic distribution. Then, factor analysis is performed to understand the relation between the response variable, number of bytes or packets per day, with dependent variables such as the source IP network, traffic direction, and country. Findings – Surprisingly, the results show that the geographical distribution is strongly dependent on the source IP network. Furthermore, even though there are thousands of users in a typical campus network, it turns out that the aggregation level which is required to observe a stable geographical pattern is even larger. Consequently, our results show a slow convergence rate to the domain of attraction of the model, specifically, we have found that at least 35 days worth of data are necessary to reach stability of the model’s estimated parameters. Practical implications – Based on these findings, conclusions drawn for one network cannot be directly extrapolated to different ones. Therefore, ISPs’ traffic measurement campaigns should include an extensive set of networks to cope with the space diversity, and also encompass a significant period of time due to the large transient time. Originality/value – Current state of the art includes some analysis of geographical patterns, but not comparisons between networks with similar populations. Such comparison can be useful for the design of Content Distribution Networks and the cost-optimization of peering agreements.This work has been partially funded by the Spanish Ministry of Education and Science under project ANFORA (TEC2009-13385), European Union CELTIC initiative program under project TRAMMS, European Union project OneLab, and the F.P.U. and F.P.I. Research Fellowship programs of Spain. The authors would also like to thank the anonymous reviewers who helped us to improve the quality of the paper

Itinerario geológico por el flanco norte del anticlinorio Honrubia-Pradales y el borde meridional de la depresión del Duero, en el entorno de Montejo de la Vega (Segovia)

El presente trabajo incluye diversas observaciones de campo en las facies terciarias de la Depresión del Duero y su zócalo constituido por materiales del Paleozoico y Hesozoico, que forman el anticlinorio Honrubia-Pradales. También, se relaciona la estructura geológica con la vegetación existente y los usos antrópicos del territorio. Se considera una excursión de interés didáctico, por la diversidad de fenómenos observables y la fácil relación que puede establecerse entre ellos.In this work several observations in the tertiary facies of the Duero's Pression and its basement contituted by materials belonging to the Paleozoic and Hesozoic ages, which from the Honrubia-Pradales anticline, ave included. It's also correlated the geological structure both with the flora and the human use of the territory. This excursion is considered didactically interesting, due to the variety of observable events and the easy relationship that can be found out between them